The division into 4 line stanzas is relatively modern. The ballad was entered in the Stationers' Register in 1586 (and still titled "A Pleasant new Ballad" a century and a half later). The oldest known copy is an unreprinted one of the 1650s in the BL 'Book of Fortune' collection. This I saw, but did not note the verse length (or even if it was divided into verses). That copy has no tune direction. Later copies cite "An excellent new tune", but, since it isn't known, it tells us nothing as far as what verse length should be. Note on the Bodley Ballads copies one is not divided into verses at all, and the other is a defective 8 lines per verse.